Below appear a number of frequently recurring questions that our customers have requested information about or help problem-solving over the years. Should you have a request that is not covered in either this section or in the highly detailed owner’s manual, please use the Contact Us page and we will make every effort to respond in a timely manner. Occasionally, due to the open nature of our company and the extensive experience embodied within, an overload of requests may necessitate more time to respond than any of us may wish for.

Should I use High Level Input Connection or Low Level Input Connection?

 Unless your amplifier does not allow for High Level Connection we always recommend using the High Level Connection. The purpose of using the High Level Input, instead of the Low Level Input, and connecting to the speaker output terminals is one of the unique secrets of REL’s success. By connecting to the high-level input on the REL from the amplifier you build forward the sonic signature of your main system, including the tonal balance and timing cues of the entire electronics chain. In the way, the REL is fed the exact signal that is fed to the main speakers. This is a very important point and together with REL’s Active Bass Controller (ABC), ensures far superior system integration of the sub-bass with the main system.

Can high and low level circuits be used at the same time?

 No, it is not effective to use the High Level Input concurrently with the Low Level Input. Where possible, please connect the High Level Input to your main L-R amplifier channels and set the processor (in a home cinema system) to Full Range or Large in the Speaker Set-up Menu. Using the High Level Input and connecting to the speaker output terminals is one of the unique secrets of REL’s success and will maximize sub-bass performance.

The primary purpose of including a single low level input is to allow for problem solving when a Class D main amp proves to have a grounding scheme that even REL Pure D™ cannot solve. It is permissible and, indeed, highly desirable to connect High Level and the .1 circuit at the same time. For more information please see REL CONNECTIVITY and REL SET UP.

My REL is humming, possible causes?

 Hum is almost always the result of a ground loop—too many grounding points resulting in induced hum coupling through the amplifier. Systems are complex devices with numerous ground attachment points. A/C mains ground varies throughout many homes, various source components can have different grounding schemes and are all a potential source of noise. The best approach to tracking noise issues is to start by disconnecting everything from the REL except for the a/c mains power. If the hum goes away, then the REL is not the origin of the grounding issue, only the victim of a problem upstream in the system. If the hum persists after the a/c test then re-connect the High Level but lift the black ground wire. If the Hum goes away, turn on some music and if the REL operates normally (it usually will) then your problem is solved (ground has been obtained through some other connection point) and the black wire should be clipped and taped so as not to make inadvertent connection in future.

Another possible solution to eliminate hum is connecting the REL to chassis ground on the main amp and connecting REL black ground to an unused line level (RCA) connection. In some markets, especially North America, using an a/c mains ground-lifting plug on source components can eliminate hum, as this is the source of the ground loop. If all else fails, disconnect the high level and connect via the low level input as your system’s ground problems are beyond the scope of this FAQ section to resolve.

How do I set-up a REL subwoofer?

 Please refer to the extensive set-up guide found here: REL SET UP. If an unusual set-up question arises, please use the Contact Us page and send in your query and we will do our utmost to respond in a timely basis.

Are REL subwoofers compatible with Class D main amps?

As much as any device possessing an additional amplifier can be, a REL is compatible with most Class D circuits. The challenge arises from the varied and complex grounding inherent to a Class D amp. Some digital amps routinely break ground as a prerequisite for digital amplification. In this instance, it is necessary to connect using low level input and .1 only.

Note: It is recommended that users NOT connect the black ground wire (High Level connection) to the negative speaker terminal on their main amplifier when connecting to a Class D main amp. Only connect if NO output is present from your REL when connected thus. Since many Class D amps are tricky to work with, it is best to avoid adding any unnecessary ground since this can result in hum or, in certain rare instances, instability in the part of the main amplifier.

Where can I purchase a replacement part for my REL?

 REL uses extremely high quality parts that have been thoroughly tested for application. If you require repair and are a UK customer please contact REL UK. If you live outside the UK, please contact the distributor in your market.

What is a high level digital cable and when would I need one?

 The REL Digital Cable is an optional accessory developed to allow Class D amplifiers to connect via High Level connection to older REL models. All current generation REL models contain the REL Pure D circuit that is the most effective means for ground isolation we can currently conceive of. Thus, if you purchase any Serie T, Serie R or Gibraltar model, rest assured that these already have our proprietary circuit and there is no need for a REL Digital Cable (Note: Please do NOT attempt to connect a REL Digital Cable to any current model as damage to your main amp and/or your REL may occur).

Home Cinema FAQ Section:

 Why does my home cinema even need a REL sub-bass system?

Perhaps the single most important upgrade in a home theater system is the addition of a high quality subwoofer, such as a REL. In fact, many customers report it being the single biggest upgrade in their home cinema. Modern home cinema is designed to meet or even surpass public theater performance, but this can only be accomplished by building a system around a high quality dedicated sub like a REL, since much of the excitement and dynamics originate with the sub. The .1 channel is a dedicated channel for unlocking the excitement and thrill in movies. Don’t shortchange your theater experience, build your home cinema around the best sub your budget can afford. Hot Ticket: start with 2 higher quality mains speakers and a REL (2.1), rather than locking oneself into 5 lesser quality speakers and a lesser quality sub (5.1). In almost every instance, the user will benefit from a more natural sound at all times, and the ability to build out the system later by adding matching center and rear channel speakers.

Why does anyone need more than one REL in a home cinema system?

The point of utilizing multiple RELs in a system, whether for film sound or stereo music, is often lost on those who assume that this suggestion is only for the bass-crazed. In fact, when set up properly the adoption of multiple RELs allows for more even distribution of bass throughout the listening space and a much more natural experience. When using the Shotgun Theater Reference Mode (see REL Technology) and using 3 or more RELs (1-main l/R high level +.1 channel, 1-center high level only, 1 rear channels high level and .1) it is possible to produce a 3 dimensional stage which places the viewer/listener inside the action taking place onscreen. This is essential for both enhancing the intimacy of smaller scenes as well as immersing the viewer/listener inside the biggest active scenes.

Are RELs really expensive? Why does my home theater even need a subwoofer the quality of a REL?

 It is possible to obtain loud, often boomy bass for special effects explosions and the like from a merely adequate subwoofer—of which there are many. The reasons to step-up to a REL are several: First, RELs are available at far lower cost than you might think. Many years ago, RELs were only available to the wealthy. With shrewd sourcing, relentless attention to detail, supply management and resourceful design, REL has managed to produce higher quality sub-bass systems at lower costs than previous years. Second, REL’s technology philosophy can be partially summarized as multiple uses, multiple benefits. Home cinema systems are usually used for much more than the occasional movie spectacular. Most home cinema systems are asked to perform multiple duties. Shouldn’t your system be able to do it all, music and movies? REL subwoofers make this possible without strain on the end user. RELs are broadly acknowledged to be the most natural sounding when playing music and, with separate controls for .1 settings, are extremely user friendly when switching between music and movies. While other subwoofers require users to constantly adjust the volume setting depending on the application, REL sub bass systems can be set once for all applications. Therefore, there is no longer a need to turn up the volume of the REL for movies and turn it back down for music because the movie setting is too loud and boomy. Finally, historically other subwoofers are not known to be the most attractive or well-finished elements in home systems. This unfortunate reality is amplified by the large size of many woofers. However, modern RELs are often the visual highlight of a system and is able to be presented with pride rather than being hidden.

Is there a real difference between the .1 (LFE) and the low level inputs?

Indeed there is a significant difference. The .1 channel is a Special Effects Low Frequency Channel and has a relatively high (120 Hz, 4th order) and aggressive crossover frequency. It should NEVER be used for any application other than a true LFE channel. The Low Level Input is, in fact, the same quality and filter type as our famous High Level Input, but in most instances can only handle 1 channel of the preamp-type signal being sent. Thus, it is useful in certain unusual applications (particularly difficult Class D amp connection, for example) to bypass the High Level Connection and use the Low Level Input.

Every other sub manufacturer just recommends connecting the .1/LFE input for theater. IS this what REL suggests?

Please see REL Technology for a more complete discussion of the merits of using our Shotgun Theater Reference Connection. We strongly recommend using BOTH High Level AND the .1 LFE channel when used in a high end theater. When doing so, it is MANDATORY that the AV processor/receiver is set to “Full Range” in its bass management. Otherwise the bass signal sent to the REL will be limited before it ever reaches the REL. REL sub bass systems have the unique capacity to produce a seamless blend of main speakers, low bass, and .1 LFE. Providing all of this information to the REL allows for a much richer and fuller sound that is more natural as well as being closer to what the studio engineers were intending to be reproduced.

Many speaker companies sell subs with their own speakers, why should I buy a REL instead of the “matching” subwoofer?

 The notion that a full range speaker manufacturer might make a “matching” sub to the main speakers is a flawed premise. Sub-bass may be the most demanding design brief in all of speaker design and the ability to do it well and reliably is beyond the abilities of almost all speaker manufacturers. The easiest way to tell if a subwoofer is a result of happenstance is to turn the sub around and look at the rear panel. Most possess low quality connectors that will oxidize and start humming in a few months or year, and usually use cheap black paint with white graphics. These are telling signs that the subwoofer was designed to produce a salable object for the lowest cost to the manufacturer. Moreover, these subwoofers usually feature drivers designed NOT to produce deep bass, a poor quality amplifier, and lack true filter capability or technology. While these subwoofers are a profit center for the manufacturer, they should be avoided at almost any cost. Stay with a specialist mark such as REL. All we want is the opportunity to show you why the .1 in 5.1 should be remarkable.




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